So I have my level blocked out but I'm not sure of the best way to approach a waterfall. What I'm trying to do is a waterfall with a room behind it which is accessible by walking through the falls. Right now what I have is a non-solid brush with a vertical panning water texture on it and it doesnt look great.

I want it to look like fast falling water but I dont know how to control the texture panning speed. Or is there a better way to do this? An animated texture for instance?

Is it possible to make a water volume that turns the player's vision blue when walking through it? But I dont want them to be able to swim up the fall...

Lastly, it would look a lot better with some mist or fog at the bottom of the falls or maybe some splashing water texture. How can I do this?

stretching a texture (obviously) makes it's respective panning speed stretched(faster), that can be used to achive such effect.(some times ago i made a map as a sort of experiment, DM-SpillwayXXL, that has a waterfall like that.)You might want to make a brush instead of a simple sheet. You can add some tidbits to make it look nicee, like foglight, smoke generator(for vapor), even some rotating decos, like boulder with transparent liqud texture skin set enviromapcurvy can imitate some turbulent water (or lava).. etc

We should have a , Making Waterfall Contest, then if there is some maps to make a map pack would be a great tutorial on having samples made by different people to see how it's done, or could be done, an InfoPack, LoL